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(ModeL) 2 Sheets-Sheet 1 T. ARMSTRONG.

PROPELLER BLADE.

' No. 535,271. Patented Mar.'5,1895.

' Jnvezaor (ModeL) 2 Sheets-Shet 2.

T. ARMSTRONG.

PROPELLER BLADE No. 535,271. Patented Mair. 5, 1895.

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NITED STATES WFFICE.

ATENT THOMAS ARMSTRONG, OF LONDON, ENGLAND.

PRO PELLER-BLAD E.

SPECIFICATION forming part of Letters Patent No. 535,271, dated March 5, 1895. Application filed April 30,1894- Serial No. 509,568. (ModeL) To all whom it may concern.-

Be it known that I, THOMAS ARMSTRONG, gentleman, a subject of the Queen of Great Britain, and residing at Leadenhall Buildings, in the cityof London, England, have invented an Improved Propeller-Blade, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to an improved propeller-blade.

The object of my said inventionis the construction of a propeller-blade of a novel kind, which, in operation, will be more efticient than propeller blades of the types hitherto commonly employed.

The blade comprises or constitutes, exactly or approximately, a segment or section of a hollow sphere, globe or ball which may be of any desired proportions.

The concavo-convex segment or section constituting the body portion of the blade is formed or provided on the rear edge of its partly spherical surface with a reversely curved rim or lip, shaped somewhat like the flaring mouth of a bell and serving to enable the propeller to be effectively used for moving the vessel sternward, when required.

One, two or more blades may be used as a propeller and the same can be made of metal or any other material and in any or such proportions, thickness or area as may be deemed applicable to ships, vessels or other bodies, aerial or marine, of any description whatsoever and as may be adaptable to the machinery available for rotary propulsion in connection with the same.

In order that my said invention may be more clearly understood I will now proceed to describe the same with reference, by way shaft.

B is the blade.

B is the spherical or approximately spherical portion of the blade.

B is the rim or lip. The rim or lip 13 is curved in the reverse direction to the main body of the propeller blade, and it is because of this reverse curvature that it can be effectively utilized in moving the vessel sternward.

The arrow, in thedrawings indicates the direction in which the blade is intended to move when running ahead. Consequently O is the leading edge, and D the following edge.

What I claim is A propeller blade composed of a segment or section of a hollow sphere and having on its rear edge a reversely curved rim or lip, substantially as and for the purpose described.

In testimony whereof I have hereunto set my hand this 20th day of April, 1894:.

THOMAS ARMSTRONG.

Witnesses:

GEO. HARRISON, T. F. BARNES. 

